Build material recovery for a three-dimensional (3d) printer

ABSTRACT

A build material recovery system for a three-dimensional (3D) printer can include a selective solidification device to create a 3D object using build material, a build processing device to separate the 3D object from unfused build material, a material separating and conditioning device to condition the unfused build material, and a material storage device to store the conditioned build material.

PRIORITY INFORMATION

This application is a continuation of U.S. National Stage applicationSer. No. 16/075,487 filed on Aug. 3, 2018, which claims priority toInternational Application No. PCT/US2017/043091 filed on Jul. 20, 2017.The contents of which are incorporated herein by reference in itsentirety.

BACKGROUND

A three-dimensional (3D) printer may be used to create different 3Dobjects. 3D printers may utilize additive manufacturing techniques tocreate the 3D objects. For instance, a 3D printer may deposit materialin successive layers in a selective solidification device of the 3Dprinter to create a 3D object. The material can be selectively fused, orotherwise solidified, to form the successive layers of the 3D object.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a method for build material recoveryfor a 3D printer consistent with the disclosure.

FIG. 2 illustrates an example of a build material recovery system for a3D printer consistent with the disclosure.

FIG. 3 illustrates another example of a method for build materialrecovery for a 3D printer consistent with the disclosure.

DETAILED DESCRIPTION

Some 3D printers can utilize a build material to create 3D objects. Thebuild material can have a powdered and/or granular form. The 3D printercan apply build material in successive layers in a selectivesolidification device to create 3D objects. The build material can beselectively fused or solidified, and a next successive layer of buildmaterial can be applied to the selective solidification device.

As used herein, the term “3D printer” can, for example, refer to adevice that can create a physical 3D object during a build process ofthe 3D printer. In some examples, the 3D printer can create the 3Dobject utilizing a 3D digital model. The 3D printer can create the 3Dobject by, for example, depositing a build material such as powder, anda binder material or fusing agent, in a selective solidification deviceof the 3D printer. As used herein, the term “selective solidificationdevice” can, for example, refer to an area of the 3D printer in which a3D object may be created. For instance, build material can beselectively solidified by the selective solidification device in a buildchamber. The build chamber can be an area in which the 3D object isformed. The build material may be deposited in successive layers in theselective solidification device to create the 3D object. In someexamples, a 3D printer can create the 3D object utilizing powder bedfusion, among other types of 3D printing. For example, “selectivesolidification” can refer to different types of 3D printing (andsolidification of a 3D object, such as, for example selective heatsintering, selective laser sintering, binder jet solidification,stereolithography, digital light processing, thermal fusion and fusingagent, selective laser melting, electronic beam melting, or laminatedobject manufacturing, among others.

In some examples, not all of the build material supplied to theselective solidification device of the 3D printer may be utilized duringa build process of a 3D object in the 3D printer. For instance, buildmaterial supplied to the selective solidification device can form partof a 3D object or can be used during the 3D printing process by may notbe solidified. For example, incidental build material may be airborneand/or may fall outside the area of a build platform during the buildprocess, and/or there may be excess build material left over at the endof the build process. The incidental and/or excess build material may bereused during the same build process and/or in a subsequent buildprocess when recovered from the selective solidification device. As usedherein, incidental and/or excess build material can be referred to as“unfused or unsolidified build material.”

Some approaches to recovering the unfused build material includeremoving a receptacle (e.g., a “build unit”) containing the 3D object,and manually removing the unfused build material. For instance, a usermay manually sift through the build and unfused build material removingthe 3D object from the unfused build material. The unfused buildmaterial can be manually placed elsewhere for use in a future build ordisposed of.

Build material recovery in accordance with the present disclosure caninclude a build material recovery system for a 3D printer integratedwithin the 3D printer. For instance, some examples can includerecovering unfused build material during and/or after a build process,recycling the recovered build material, and providing the recycled buildmaterial to a selective solidification device of the 3D printer for usein an ongoing or a subsequent build process. The build material recoverysystem can recycle and condition the unfused build material for the usein the build process or store it for future use.

Such an example can reduce the quantity lost build material,contaminated build material (e.g., contaminated by bugs, hair, otherbuild material, etc.), and human exposure to build material. Further, anexample including conditioning of build material can result in animproved state of recycled build material, resulting in improved 3Dobjects.

FIG. 1 illustrates an example of a method 100 for build materialrecovery for a 3D printer consistent with the disclosure. At 102 and104, recycled build material and/or fresh build material can be loadedinto a selective solidification device for creation of a 3D object at106. For instance, a mix of build material can be loaded into aselective solidification device. The mix can range, for example from 100percent fresh build material to 100 percent recycled build material,with graduations in between.

As used herein, recycled build material includes build materialrecovered from a previous or current selective solidification processand fresh build material includes new build material that is not aresult of recovery and/or recycling. Selective solidification caninclude the use of mixed recycled and fresh build material, just freshbuild material, or just recycled build material. For instance, aparticular mix ratio may be desired for a particular 3D object. Examplemix ratios can include, but are not limited to: 100 percent fresh, 0percent recycled; 20 percent fresh, 80 percent recycled; and 0 percentfresh, 100 percent recycled.

At 106, a 3D object can be created using selective solidification suchas, for instance, selective heat sintering, selective laser sintering,binder jet solidification, stereolithography, digital light processing,thermal fusion/fused deposition modeling, selective laser melting,electronic beam melting, laminated object manufacturing, among others.

At 108, unfused build material can be extracted from the selectivesolidification device. For instance, unfused build material can beseparated from the 3D object via a build processing device. In someexamples, the build processing device can separate the 3D object fromthe unfused build material using airflow and/or vibration to extract theunfused build material from the selective solidification module. Forinstance, the airflow and/or vibration can occur for periods of timethroughout the extraction process.

In some examples, the separation can include instances in which littleto no air passes through holes at the bottom of the selectivesolidification device and/or a 3D printed object recovery zone. Forinstance, the holes can allow unfused build material to flow out of theselective solidification device and/or the 3D printed object recoveryzone, but the air flow may not go through until the separation iscomplete. With respect to vibration, vibrating can move unfused buildmaterial around, allowing it to fall into the holes and be pulledthrough a transport device. The unfused build material can betransported to a material separating and conditioning device.

The 3D object can be recovered at 110. For instance, the 3D object,which can also be referred to as a printed object, can be retrieved froma 3D printed object recovery zone. The 3D printed object recovery zonecan include a receptacle to house the 3D object. It can have a lid forusers to lift for access to the 3D object, and in some examples the 3Dprinted object recovery zone can include task lighting and tools forcleaning the 3D object. In some instances, the 3D printed objectrecovery zone can include a platform that automatically lifts to presentthe 3D printed object. The 3D printed object recovery zone can includean airflow or vacuum source, in some examples, to collect unfused buildmaterial.

At 112, unfused build material can be separated from air using amaterial separating and conditioning device. In some examples,separation can include cyclonic separation or blow/settling boxseparation, among others. For example, unfused build material can betransported in an air stream for portions of a material cycle. In suchan example, unfused build material from selective solidification deviceand/or the 3D printed object recover zone can be transported bypneumatics. In order to recover that unfused build material, theair/build material mix can be separated.

Subsequent to the separation, waste can be collected at 114. In someexamples, particles may remain in the air stream. In such an example, afilter can be used to achieve desired separation (e.g., totalseparation). Those removed particles can be waste trapped in the filter,and as a result, do not end up in the recycled build material. A sieve,which can include a mesh screen for example, can process the recycledbuild material. What is left on the sieve is waste, while what passesthrough can be used as recycled build material. Examples of waste lefton the sieve can include impurities such as fibers or hair, forinstance.

The material separating and conditioning device can condition theunfused build material at 116, 118, and/or 124. Unfused build materialcan be conditioned to improve a state of the unfused build material andimprove efficiency in a subsequent or same build process. Conditioningtypes 1, 2, and 3 can be the same or different conditioning types, andcan include, for instance, cooling the build material, deionizing thebuild material, and adding or removing humidity from the build material,among others. Conditioning can result in desired properties of theunfused build material such as a desired size, shape, consistency,and/or neutral state (e.g., not electostatically charged). Theseproperties can be specified for particular 3D objects in some examples.

At 120, the material separating and conditioning device can classify theunfused build material and/or remove contaminants from the unfused buildmaterial. Classification can include, for instance, removing particleswithin the unfused build material of a particular size. Put another way,particles within the unfused build material that are outside of athreshold (e.g., too large or too small) can be removed. The particlesoutside of the threshold may be undesired such that they can result in adefective build if used in the build process. In some examples, a sievecan be used during classification to separate the desired from theundesired particles. More than one sieve can be used in some examples.For instance different sieve sizes can be used to separate differentparticle sizes. The particles outside of the threshold can be collectedand/or removed as waste at 122.

Conditioning at 116, 118, 124, and classification and/or contaminantremoval at 120 can occur in different orders, and may not occur in theorder illustrated in FIG. 1 in some examples. While three conditioningtypes and one classification and contaminant removal are illustrated inFIG. 1, more or fewer conditioning types, classifications, and/orcontaminant removals can be utilized. A combination of conditioning,classification, and/or contaminant removal can be determined based onwhich combination results in the build process most efficient (e.g.,desired state, size, texture, etc. of the build material).

At 126, subsequent to conditioning and/or contaminant removal, theunfused build material can be transported to a material storage devicefor storage of the unfused build material. The material storage devicecan include, for instance, a vessel or hopper or material cartridge tofeed a selective solidification device for a 3D object.

FIG. 2 illustrates an example of a build material recovery system 230for a 3D printer consistent with the disclosure. System 230 can beintegrated within the 3D printer in some examples. For instance, system230 can be at least partially contained within a housing of the 3Dprinter. In some examples, fresh and/or recycled build material andagents can be loaded (e.g., via cartridges) into system 230, and the 3Dobject, waste, unused build material, cartridges, vessels, hoppers orother products can come out of the 3D printer. Other products, waste,etc. can be collected and housed within system 230 and the 3D printerhousing system 230.

System 230 can include selective solidification device 234 for creationof a 3D object using build material. Selective solidification device 234can include carriages 256-1, 256-2, and a third carriage (notillustrated in FIG. 2) for use in creation of the 3D object, along withagent cartridges 240 (e.g., color agent cartridges, thermal agentcartridges, etc.). The third carriage can operate substantiallyorthogonal to carriages 256-1 and 256-2. Carriages 256-1 and 256-2 canbe in-line with one another and can operate on a same track. In someexamples, carriages 256-1 and 256-2 can work with the third carriage tocreate a 3D object. The third carriage can include a spreader used tospread build material during selective solidification. The carriages canbe fed build material from material storage devices 252 and 254 and canbe fed agents from agent cartridges 240 via an agent conveyance system238 for use in a selective solidification process.

Carriage 256-1 can lay down build material (e.g., fed from materialstorage devices 252 and 254), and carriage 256-2 can house a print headfor applying agents fed from agent cartridge 240. Carriages 256-1 and256-2, along with the third carriage, can work in concert to fuse buildmaterial layer-by-layer until the 3D object is complete. For instance,carriage 256-1 can warm and spread layers of the build material whilecarriage 256-2 prints on the powder. During selective solidification,certain build material may not absorb energy, leaving it unfused (e.g.,loose, unsolidified, powdery, etc.). Upon completion of the 3D object,unfused build material can be recovered for use in a future build orstored. In some examples, during selective solidification, unfused buildmaterial can be recovered and used in the current build (e.g., in-jobreclamation). The recovery, in some examples, can be automatic such thatit can be performed with limited or no user input and/or with limited orno prompting.

In some examples, selective solidification device can be enclosed duringthe selective solidification process, and an airflow or vacuum sourcecan be present. In such an example, unfused (e.g., airborne) buildmaterial can be collected by the airflow or vacuum source for use in thecurrent selective solidification process and/or a future selectivesolidification process.

System 230 can include fresh build material cartridge 246 and recycledbuild material cartridge 232. An example build material cartridge 250 isillustrated outside of system 230. Fresh build material cartridge 246can house fresh build material that feeds fresh material to storagedevice 252. Recycled material cartridge 232 can house recycled buildmaterial that feeds one of two recycled material storage devices 254-1.The other recycled material storage device 254-2 can be fed directlyfrom the build processing device 242 and material separating andconditioning device 244. While two recycled material storage devices 254and one fresh material storage device 252 are illustrated, more or fewermay be present. When a build material cartridge 246, 232 has a low levelof build material, what is remaining can be deposited into itsrespective build material storage device 252, 254-1, and the now-emptybuild material cartridge can be replaced with a full build materialcartridge such as cartridge 250. This can prevent system 230 fromrunning out of build material in the middle of a selectivesolidification process. In some examples, build material in buildmaterial storage devices 254 can be loaded into material cartridges,such as cartridge 250, for use in other systems, 3D printers, or 3Dobjects or stored for future builds. In some instances, build materialcartridges 246, 232 can completely empty into an material storagedevices 252 and 254-1, respectively.

The 3D object can be collected by a user from 3D printed object recoveryzone 236. For instance, the 3D printed object recovery zone 236 can bean area where the 3D object is placed when completed, and a user candust off the 3D object, view and examine the 3D object, etc. A base ofthe 3D printed object recovery zone 236 can have holes, in someexamples, for unfused build material to fall through for the buildmaterial recovery process. 3D printed object recovery zone 236 can beenclosed until the 3D object is complete and a lid is lifted eithermanually or automatically.

Subsequent to the creation of the 3D object, build processing device 242can be used to separate the 3D object from unfused build material. Buildprocessing device 242 can use airflow and/or vibration to extract theunfused build material from selective solidification module 234 and/or3D printed object recovery zone 236. For instance, air, vibration, or acombination of the two can be used to pull loose, unfused build materialaway from the 3D object. In some examples, build processing device 242,can subsequently transport the unfused build material to the materialseparating and conditioning device 244.

Material separating and conditioning device 244 can separate the unfusedbuild material from air, remove particles of a size outside of athreshold, remove contaminants from the unfused build material, and/orcondition the unfused build material prior to transport to materialstorage devices 254 or selective solidification device 234 or materialcartridge 232. Conditioning can include, for instance, cooling,deionizing, de-agglomerating (e.g., milling, grinding, etc.),humidifying, and/or drying the build material, among others.

Material storage devices 254 can store the conditioned build material.Dosers on the bottom of each of build material storage devices 252, 254can be used to feed a build in selective solidification device 234 viatransport device 248. For example, system 230 can include transportdevice 248 that can work as a build material conveyance system totransport build material throughout system 230. Build material can betransported through system 230 pneumatically. For example, system 230can include a pneumatic system for transporting build material betweenbuild material storage devices 252 and 254 and another pneumatic systemfor separation and extraction of unfused build material and vacuumfunctions including pulling air through holes in 3D printed recoveryzone 236 or build processing device 242 during separation of fused andunfused build material.

The term “pneumatic” can, for example, refer to using gas, which may bepressurized, to exact work on a body. For example, pressurized gas maybe utilized to move build material from one location to another locationin the 3D printer. The pressured gas may be utilized to move the buildmaterial in piping included in the 3D printer. The piping can be part ofbuild material transport system 248. As used herein, the term “gas” can,for example, refer to a substance which expands to fill an availablespace. Gas can be a gas mixture in some examples.

Transport device 248, in some examples, can transport conditioned,separated, decontaminated, and/or mixed build material from a materialstorage devices 254 to the selective solidification device 234 for usein a different build or stored in material cartridge 232. For instance,the build material can be transported to the third carriage forspreading during selective solidification. Transport device can include,for example, the pneumatic system as described above.

In some examples, recycled build material from material storage devices254 can be mixed with fresh build material from material storage device252 using transportation device 248. For instance, dosers at the bottomof material storage devices 254 and 252 can dose a particular amount(e.g., by volume, mass, etc.) of build material near-simultaneously suchthat the build materials can mix in transit to the selectivesolidification device 234. As used herein, near-simultaneously caninclude dosing without meaningful breaks or within a particular margin,range, and/or threshold time. The mixing can be done at a particularratio, for instance at 80 percent recycled and 20 percent fresh.However, examples are not so limited. The build material used in a 3Dobject can be all fresh, all recycled, or a combination of the two Theparticular ratio can vary based on, for instance, a user's preferences,the type of 3D object, and/or availability of build materials, amongothers.

System 230 and the 3D printer housing can be an enclosed systemincluding removable components such as build material cartridges 246 and232, build material storage devices 252 and 254, and other portions ofsystem 230 including filters, sieves, agents and agent cartridges,portions of the build processing device 242, portions of materialseparating and conditioning device 244, portions of selectivesolidification device 234, portions of 3D printed object recovery zone236, and portions of transport device 248, among other components. Thesecomponents may be removed for cleaning and/or servicing, or buildmaterial change, for instance.

FIG. 3 illustrates another example of a method 360 for build materialrecovery for a 3D printer consistent with the disclosure. In someexamples, method 360 can be performed automatically. Automatically, asused herein, can include method 360 being performed with limited or nouser input and/or with limited or no prompting.

At 362, method 360 can include selectively solidifying a 3D object usingbuild material. For instance, build material can be a mix of recycledand fresh build material, and at 364, method 360 can include separatingthe 3D object from unfused build material. In some examples, solidifyingthe 3D object can include using a particular ratio of recycled to freshbuild material, and can in some examples include using only one of thetypes of build material. The unfused build material, in some examples,can be separated using a build process device and/or a materialseparating and conditioning device.

Method 360, at 366 can include preparing the unfused building material.Preparing the unfused build material can include iterativelyconditioning the unfused build material at 368, classifying the unfusedbuild material at 370, and removing contaminants from the unfused buildmaterial at 372. For example, the unfused build material can beconditioned, classified, and/or decontaminated until a desired thresholdstatus (e.g., size, shape, texture, consistency, etc.) of the buildmaterial is met. In some examples, waste material can be collectedsubsequent to classifying the unfused build material and removingcontaminants from the unfused build material. For instance, contaminantsfound in the build material can be removed as waste.

At 374, method 360 can include transporting the prepared build materialto a material storage device in response to reaching a thresholdpreparation status. For instance, once the desired threshold status ismet, the prepared build material can be transported via a transportdevice for use in selective solidification of a different 3D object orthe same 3D object. In some examples, the prepared build material can bemixed with fresh build material during transport.

As used herein, “logic” is an alternative or additional processingresource to perform a particular action and/or element described herein.Logic may include hardware. The hardware may include processingresources such as circuitry, which are distinct from machine readableinstructions on a machine readable media. Further, as used herein, “a”thing may refer to one, or more than one of such things. For example, “awidget” may refer to one widget, or more than one widget.

The figures follow a numbering convention in which the first digit ordigits correspond to the drawing figure number and the remaining digitsidentify an element or component in the drawing. Similar elements orcomponents between different figures may be identified by the use ofsimilar digits. For example, 102 may reference element “02” in FIG. 1,and a similar element may be referenced as 202 in FIG. 2.

The above specification, examples and data provide a description of themethod and applications, and use of the system and method of the presentdisclosure. Since many examples may be made without departing from thespirit and scope of the system and method of the present disclosure,this specification merely sets forth some of the many possible exampleconfigurations and implementations.

What is claimed is:
 1. A build material recovery device for athree-dimensional (3D) printer, comprising: a material separating andconditioning device to iteratively, until a threshold preparation statusis met: condition unfused build material separated from a 3D objectcreated at the printer; and classify the unfused build material.
 2. Thebuild material recovery device of claim 1, wherein the materialseparating and conditioning device is further to separate materials byseparating the unfused build material from air.
 3. The build materialrecovery device of claim 1, wherein the material separating andconditioning device is further separate materials by removing particlesof a particular size outside of a threshold from the unfused buildmaterial.
 4. The build material recovery device of claim 1, wherein thematerial separating and conditioning device is further to condition theunfused build material using at least one of cooling, deionizing,de-agglomerating, humidifying, and drying of the unfused build material.5. The build material recovery device of claim 1, wherein the materialseparating and conditioning device is further to: remove, from theunfused build material, contaminants introduced from outside sources;and collect waste material subsequent to removal of contaminants fromthe unfused build material.
 6. The build material recovery device ofclaim 1, wherein the material separating and conditioning device islocated within a build chamber with a selective solidification deviceand a build processing device.
 7. The build material recovery device ofclaim 1, wherein the material separating and conditioning device is torecover the unfused build material as it is separated from the 3Dobject.
 8. A build material recovery system for a three-dimensional (3D)printer, comprising: a material separating and conditioning device toiteratively, until a threshold preparation status is met: condition theunfused build material; remove, from the unfused build material,contaminants introduced from outside sources; and remove build materialof a size outside the threshold preparation status from the unfusedbuild material; and a transport device to: mix the separated andconditioned build material with fresh build material at a particularratio; and transport the mixed build material to a selectivesolidification device.
 9. The build material recovery system of claim 8,wherein the selective solidification device is located within a buildchamber with the material separating and conditioning device.
 10. Thebuild material recovery system of claim 8, further comprising a buildmaterial storage device to store the separated and conditioned buildmaterial prior to transportation.
 11. The build material recovery systemof claim 8, further comprising a build processing device to use airflowand vibration to separate a 3D object from the unfused build material.12. The build material recovery system of claim 8, wherein the transportdevice is to transport build material throughout the build materialrecovery system pneumatically.
 13. The build material recovery system ofclaim 8, further comprising material storage devices to dose the freshbuild material.
 14. The build material recovery system of claim 8,further comprising a 3D object recovery zone for 3D object recoverysubsequent to the unfused material separation.
 15. A method for buildmaterial recovery for a three-dimensional (3D) printer, comprising:preparing unfused building material, comprising iteratively:conditioning the unfused build material; classifying the unfused buildmaterial; and remove, from the unfused build material, contaminantsintroduced from outside sources; and in response to reaching a thresholdpreparation status, transporting the prepared build material to amaterial storage device.
 16. The method of claim 15, further comprisingtransporting prepared build material from the material storage devicefor use in selective solidification of a 3D object.
 17. The method ofclaim 16, further comprising mixing the prepared build material withfresh build material during transport.
 18. The method of claim 15,further comprising collecting waste material subsequent to classifyingthe unfused build material.
 19. The method of claim 15, wherein themethod is performed automatically.
 20. The method of claim 15, whereinconditioning the unfused build material comprises at least one ofcooling, deionizing, de-agglomerating, humidifying, and drying of theunfused build material.